West Ham moved into the top half of the Premier League table and compounded Wigan's woes with a 2-0 victory at Upton Park on Saturday.
Goals in either half to Matt Jarvis and Kevin Nolan proved the difference as the hosts held off a strong second-half performance from Wigan to earn victory.
The result leaves Wigan in 18th place, still three points from safety and with a real challenge to maintain their top-flight status.
Sam Allardyce's men were struggling to deal with Wigan's fluid attacks early on, but after Antolin Alcaraz had a tame first shot of the match the hosts eventually fashioned a chance of their own when James Collins' glanced header was met by Nolan, who could only divert the ball over.
It was nearly 1-0 at the other end immediately when Callum McManaman was put through one-on-one but Jussi Jaaskelainen stood firm to deny the Wigan winger.
Joel Robles then palmed Nolan's volley away, before West Ham went in front, albeit against the run of play.
The goal came when the impressive Jarvis cut inside from the left and whipped in a dangerous cross which eluded the Wigan defence and Robles before nestling in the far corner.
After Nolan had a penalty appeal waved away, Ricardo Vaz Te darted in front of Joel Robles to meet Gary O'Neil's dangerous cross, but could not divert his header on target as the hosts continued to impose their dominance.
But Wigan started brightly after the break and Arouna Kone nearly levelled matters with a 25-yard volley.
At the other end, Andy Carroll hammered an effort wide before Robles was called into action, stopping a dangerous Mohamed Diame strike.
Wigan were continuing to press and, after substitute James McArthur tested Jaaskelainen with a fierce long-range strike, Jean Beausejour was denied by the West Ham goalkeeper as he tried to curl an effort into the top corner.
Jaaskelainen was the hero again as he produced a stunning low stop to keep out McArthur's driven effort from 12 yards out.
But the hosts countered in the best way possible, wrapping up victory with 10 minutes left as Nolan got on the end of Carroll's attempted bicycle kick to produce an excellent acrobatic finish of his own.
Carroll nearly got on the scoresheet himself as he broke past the Wigan defence, but with Robles rushing out he snatched at the shot and it went well wide.
West Ham held on though and move into the top half of the table, while Martinez's men have a real scrap to survive.